Another day, and another departure at Snapchat’s parent, Snap. The company has announced in an SEC filing that Imran Khan will be stepping down as chief strategy officer, a role he has held since 2014.

(Since publishing this post, we have learned that Khan is leaving to start his own investment firm. More here.)

This is the latest in a series of executive moves at the company since it went public last year. The latest news has sent Snap’s stock down in pre-market trading to as low as $9.75 — around one-third of the value of the stock when it first listed in March 2017.

The company said that Khan informed Snap on September 6, and he did not give a specific reason except to pursue other opportunities and that “Mr. Khan has confirmed that this transition is not related to any disagreement with us on any matter relating to our accounting, strategy, management, operations, policies, or practices (financial or otherwise).” Khan will stay on as CSO for a transition period, and his last day has not been determined.

Although there is no reason given for his leaving, and it sounds like he’s moving to a new opportunity, the change will raise questions about the health of the company.

In its last earnings in August, Snap showed signs of growing its fledgling ad business and had beat analyst’s financial expectations, but it also lost 3 million users and continues to face stiff competition from Facebook (which keeps copying its best features), and general attrition of interest from its millennial user base as it moves to the next big thing.

Coupled with this, the company’s CEO has had a strong hand in running the company, an approach that has its pros and cons.

“Imran has been a great partner building our business. We appreciate all of his hard work and wish him the best” said Evan Spiegel, CEO and co-founder of Snap, in a statement.

“There is never a perfect time to say goodbye, but we have a stellar leadership team in place to guide Snap through the next chapter, and I plan to stay on to ensure a very smooth transition” said Khan in his own statement noted in the SEC filing.

Snap — then still a very fast-moving startup called Snapchat, hot off the heels of rebuffing a $3 billion offer from Facebook, and just ahead of a reportedly $30 billion offer from Google — made big waves in 2014 when it hired Khan from his role as a star banker at Credit Suisse.

The move turned out to be part a wave of hires by outsized tech companies to bring in financial big guns, ushering in a different wave of thinking as these businesses increasingly interfaced with the finance world as large, multinational businesses. (Other related hires included Anthony Noto at Twitter, and Ruth Porat at Google.)

All being relative, Khan has had a longer run at Snap than many of the other top brass who have come and gone, some staying for little more than a year — a detail that is ironic in the context of the Snapchat app’s ephemerality, but otherwise potentially very destabilising for the company.

Snap said that it is now in a transition agreement with Khan regarding his stock units. While with the company he will continue to get RSUs, and that he will continue to get a “pro rata number of unvested RSUs for each day worked after your most recent vesting date as of your last day, provided that you continue to comply with your Employee Confidential Information and Inventions Assignment Agreement signed on December 5, 2014.”

We have reached out to Khan to see if he will give more details about what he is doing next, and will update this story as we learn more.